raise an exception when invalid port argument is provided to add_vxlan
function.

Change-Id: I652379835738cc39a54f5ddf92250fe0f675f379
replace dict to {}
more verbose error message in ensure_vxlan_bridge

Change-Id: I22f6d1517f7ae393984787df83b70a31dfc48daf
move vxlan_port check to agent startup
more verbose message in ensure_physical_in_bridge

Change-Id: If1985209e93f7ae02bf80f98c125fd37220b6a21
proper default values for VXLAN settings

Change-Id: Idd3d28039e487e70b3142aff2a6f5229bcdaa900
remove comment from l2network_models_v2

Change-Id: Id2c5b9c65274f859f07b35909cf13495befe9621
make delete_network more readable

Change-Id: Iff8f843c0747ce2c0f81a862a3f65eb4dfb8b479
more fixes

Change-Id: If0d56927c915c489a629047ffd245f8a37092e35